Orbital Eccentricity and Unbalanced Magnetic Pull in Salient Pole Synchronous Machines

This paper presents a model that describes the Unbalanced Magnetic Pull (UMP) as an eccentricity function. An original model of the modified radial air-gap length is introduced as it is a function of the eccentricity and modulates the amplitude of the magnetic flux density spatial distribution. Saturation is considered as a linear function of the air-gap length, thus modulating the magnetic field. Seven case studies are presented comparing classical methodology with the proposed one. Two of these cases were also calculated applying the Finite Element Method (FEM). The proposed methodology offered more realistic results should the FEM be taken as reference. Finally, the graphical result of a UMP triggered by a dynamic eccentricity is shown and the expected resulting force that followed the orbital eccentricity is depicted clearly. It is worth noting that this is the first paper to model the dynamic eccentricity.